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Observations of ultra-hot Jupiters indicate the existence of thermal inversion in their atmospheres with day-side temperatures greater than 2200 K. Various physical mechanisms such as non-local thermal equilibrium, cloud formation, disequilibrium chemistry, ionisation, hydrodynamic waves and associated energy, have been omitted in previous spectral retrievals while they play an important role on the thermal structure of their upper atmospheres.We aim at exploring the atmospheric properties of WASP-19b to understand its largely featureless thermal spectra using a state-of-the-art atmosphere code that includes a detailed treatment of the most important physical and chemical processes at play in such atmospheres.We used the one-dimensional line-by-line radiative transfer code PHOENIX in its spherical symmetry configuration including the BT-Settl cloud model and C/O disequilibrium chemistry to analyse the observed thermal spectrum of WASP-19b. Results. We find evidence for a thermal inversion in the day-side atmosphere of the highly irradiated ultra-hot Jupiter WASP-19b with Teq ~ 2700 K. At these high temperatures we find that H2O dissociates thermally at pressure below 10^-2 bar. The inverted temperature-pressure profiles of WASP-19b show the evidence of CO emission features at 4.5 micron in its secondary eclipse spectra.We find that the atmosphere ofWASP-19b is thermally inverted.We infer that the thermal inversion is due to the strong impinging radiation. We show that H2O is partially dissociated in the upper atmosphere above about tau = 10^-2, but is still a significant contributor to the infrared-opacity, dominated by CO. The high-temperature and low-density conditions cause H2O to have a flatter opacity profile than in non-irradiated brown dwarfs.Altogether these factors makes H2O more difficult to identify in WASP-19b.
Context: When the planet transits its host star, it is possible to measure the planetary radius and (with radial velocity data) the planet mass. For the study of planetary atmospheres, it is essential to obtain transit and occultation measurements at
We aim to construct a spectral energy distribution (SED) for the emission from the dayside atmosphere of the hot Jupiter WASP-46b and to investigate its energy budget. We observed a secondary eclipse of WASP-46b simultaneously in the grizJHK bands us
High resolution precision spectroscopy provides a multitude of robust techniques for probing exoplanetary atmospheres. We present multiple VLT/ESPRESSO transit observations of the hot-Jupiter exoplanet WASP-19b with previously published but disputed
We present an occultation of the newly discovered hot Jupiter system WASP-19, observed with the HAWK-I instrument on the VLT, in order to measure thermal emission from the planets dayside at ~2 um. The light curve was analysed using a Markov-Chain Mo
We present a empirical study of orbital decay for the exoplanet WASP-19b, based on mid-time measurements of 74 complete transits (12 newly obtained by our team and 62 from the literature), covering a 10-year baseline. A linear ephemeris best represen